Made from fully tempered soda lime glass, the KeepCup Brew it is durable, shock resistant, dishwasher safe and can withstand high temperatures. Although the glass is toughened, it is breakable.  We use silicone as a separable component as an insulating barrier; it has great non-slip and thermal resistant qualities, and is BPS and BPA free. The base material of silicone is sand, however because it sets with heat, once the molten silicone material is set, it cannot be remoulded. Silicone cannot be recycled in domestic recycling, it requires a dedicated commercial collection. Where a commercial recycling closed loop exists, silicone can be desiccated and downcycled. Lid off can be heated to 100°C/ 212°F degrees Made from toughened soda lime glass – not unbreakable, but surprisingly durable Size 12oz/ M/ 340ml